[libvirt] Fix locking in qemudDomainMemoryStats

[Daniel P. Berrange]

On Fri, Mar 05, 2010 at 02:13:05PM -0600, Adam Litke wrote:
> When adding domainMemoryStats API support for the qemu driver, I didn't
> follow the locking rules exactly.  The job condition must be held when
> executing monitor commands.  This corrects the segfaults I was seeing
> when calling domainMemoryStats in a multi-threaded environment.
> 
> If this patch is accepted, I would also consider it a candidate for the
> 0.7.6 stable patch stream (if such a thing exists).  Thanks.

Since we're doing regular monthly releases we don't produce any formal
patch streams currently, leaving it upto os distros

> 
> Signed-off-by: Adam Litke <agl at us.ibm.com>
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index b8b7916..a9023da 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -7526,6 +7526,9 @@ qemudDomainMemoryStats (virDomainPtr dom,
>          goto cleanup;
>      }
>  
> +    if (qemuDomainObjBeginJob(vm) < 0)
> +        goto cleanup;
> +
>      if (virDomainObjIsActive(vm)) {
>          qemuDomainObjPrivatePtr priv = vm->privateData;
>          qemuDomainObjEnterMonitor(vm);
> @@ -7536,6 +7539,9 @@ qemudDomainMemoryStats (virDomainPtr dom,
>                          "%s", _("domain is not running"));
>      }
>  
> +    if (qemuDomainObjEndJob(vm) == 0)
> +        vm = NULL;
> +
>  cleanup:
>      if (vm)
>          virDomainObjUnlock(vm);
> 
> 

ACK, this is definitely required :-)


Daniel
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